Amplifier



Patented Sept. 23, 1924,

PATENT OFFICE.

HENRY K. SANDELL, OF CHICAGO, ILLINOIS.

AMPLIFIER.

Application filed February 15, 1923. Serial No. 619,144.

T all whom t may concern:

Be it known that I, HENRY K. SANDELL, a citizen of the United States,residing at 1640 Farragut Avenue, Chicago, in the county of Cool; andState of Illinois, have invented new and useful Improvements inAmpliers, of which the following is a specification. y

The present invention relates to improve ments in amplifying devices andmore particularly in amplifiers intended for use in connection withvibrating diaphragms such as those of phonograph sound boxes, telephoneand wireless receivers and the like. It will be fully understood fromthe following description illustrated by the accompanying` drawings inwhich- Fig. l is a vertical section view through an amplifier embodyingthe invention.

Fig. 2 is a horizontal view on the line 2`2 of Figure l.

in accordance with the present invention, 'the amplifier constructed insuch a manner as to substantially eliminate resonance and prevent theproduction of vibration of the amplifier itself and resultantinterference with the amplification and propagation of the sound waveswhich it is desired to amplify.

Referring more particularly to the drawings, the numeral 5 indicates abase board forming one wall. of the amplifier and preferably constructedof substantially triangular shape. The base board 5 is substantiallyflat in the form of construction shown. F rom it rise two supportingmembers 6, which serve as a support for the amplifier wall T oppositethe wall 5. The amplier wall 7 is formed of wood, beaver board, or othersuitable material and is given a pronounced curvature from the mouth ofthe amplifier to its throat. Between the upper and lower wallmembers 5and 7, there are secured to the supporting members 6 the side walls 8,which are curved from the 45 mouth of the amplifier to its throat, thecurvature of the side wall members 8 being substantially the same. Theseside wall members are constructed of any suitable non-resonant material,for example, lead. At the throat of the amplifier there is seh cured tothe walls 5 and 7 and to the supporting members 6 a nipple 9 providedwith a gradually enlarging portion 10 which. enters the amplifier and asmaller external portion ll to which the receiver l2, or other devicecontaining a vibrating diaphragm is attached. It will be noted from theabove description of the construction that the walls 5 and 7 areconstructed of vibratable 60 or resonant material of differentcurvatures,

so that they do not have identical vibration characteristics. The sidewalls 8, which are formed with like curvatures, are of nonresonant orvibratable material. As a result of this form of construction,vibrations cannot be set up in the amplifier as a rcsult of the rates ofvibration of the sound waves passing through it; in short, theconstruction as a whole, is substantially nonresonant.

Jdlthough the present invention has been shown in connection with thespecific details of a construction embodying the same, it is notintended that these details shall be regarded as limitations upon thescope of the invention except in so far as included in the accompanyingclaim.

l claim:

An amplifier having a substantially fiat bottom wall of triangularshape, supporting members rising therefrom, a top wall resting upon saidsupporting members and curved from the mouth of the amplifier to itsthroat, and curved side members of nonvibratable material secured tosaid supporting members. v

HENRY K. SANDELL.

